Braking mechanism



April 21, 192s.

R. BANcRoFrr ,Bamm mscnmsm Fned sept. 13. 1923 2 sheets-sheet ,1

l as' A TTQRNEY' 1,534,293 R. BANCROFT 4 BRAKING MECHANISM Filed Sepi. 13. 1923 ZSheetS-Sheet 2 llunfflfrll/lflllrlr IN VEN TOR.

/foyl H/rmoff. A

BYW l ATTORNEY *Mmmm ec `with "the bject gofmy 0 ject w braking @Still uitfle to provide nechamsm adaplted t invention! "iS 5to@ provide mkmg, medllaillm JOl: revolving: Shafts of which@ aligned shafts 8 and 9 Which are operatively connected and driven through suitable dif 'lierential gearing arranged in a housing' 11. )peratively associated With the shafts S and 9 are independent pressure generating means here shown in the form of force pumps 12. Each of the latter includes a cylinder 13 suitably positioned in fixed relation to the axis of the associated shaft, and having a piston 1l reciprocatively mounted therein. Movement of the pistou is arranged to be eifel-ted by convertini' the rotative motion of the shaft into recti mear movement. is here shoiv said conversion is made by means of an eccentric disc l5 fixed on the shaft and engaged by a strap 16 provided on the outer end of a connecting rod 1S which is pivotally secured to the piston.

The piston 1-lis preferably provided with a suitable intake valve 17. As illustrated, the cylinder 9 is open at the end nearest the shaft and is closed at the other end, the latter end having arranged therein a suitable outlet valve 1S'- diseharging into a discharge passage 20.

The discharge passages 20 of both of the pumps are connected together to form a common passage or cha uber Q1, and means are provided, such as a control valve 22, for controlling the discharge of the fluid from said chamber. The Valve Q2 arranged to be manipulated manually by means of a rod 23 connected to a suitable lever @i positioned Within operative reach of the driver. The valve is arranged to be norn'ially held in open position by means of a spring suitably connected to the lever.

The discharge passages and chamber are of such cross-sectional area that when the valve 22 is in open position an unrestricted discharge of fluid from the pumps permitted. In this manner since there is practically no resistance to pumping there will be no braking force exerted in the associated shaft. However, when the control valve 2Q is operated to restrict the discharge of duid, n. corresponding back pressure ivill be developed and a proportionate braking force will be produced opposing rotation of the shafts.

By virtue of the fact that both pumps discharge into the common chamber Q1, it Will be evident that, notwithstanding' the fact that the shafts may rotate at different relative speeds, the available braking forces acting on said shafts Will at any instant be equal. It is to be further noted that the pressure in the chamber 21 will reach the ma: lum value only after a number of strokes of one or both pistons, thereby avoiding the possibility of a too sudden application of the maximum braking force. Furthermore, the danger of skiddmg is lessened on account of the reciprocative action of the device,

since a true locking of the Wheels is prevented, through the alternate application und release of the braking pressure.

In Figures l to 6, a modi lied forni of tin` invention is shown. ln this embodiment, the force of con'ipression and corre"L braking reaction are varied b v cha relative positions of the cylinder Spect to 'the axle. rlhe cylinder case, is formed so that the bore lei Y of exceeds tvvice the length or a, piston stroke, thus allowing a change in the relative positioning of the cylinder and asile through the length of a complete cfliroke. here shovvn, the cylinder is afforded the sided movement by being liivotallj,v snspended on parallel links 31, movement thereof being` eliected by means of a rod suitably connected to the links and operatable by the driver through a suitable arrangement of levers (not shown). Formed in tbc Walls of the cylinder are openings which serve both as inlet and outlet ports for which the piston 29 driven by the axle functions as a slide valve. The openings 28 are positioned and formed to alloiv the necessary clearance of the piston connecting-rod 83. It vvill new be evident that when the cylinder is in a position furthest removed from the shaft as shown in Figure l the apertures SES Will provide an outlet from the cylinder throughout an entire stroke of the piston, thereby preventing the creation of pressure in the cylinder and permitting the idling of the device. lf the cylinder is positioned nearer the shaft as sboivn in Figure 5, the apertures 28 serve as outlet valves for only part of a piston stroke the remaining` portion of the stroke serving to compress the imprisoned air and thus create a back pressure for b aking llhen the cylinder is positioned neares the shaft, as shoivn in Figure. 6, the apertures do not communicate With the compression chan'iber during any part of a piston stroke and a maximum compression is thus provided. From the foregoing it will be evident that the magnitude of the braking force is entirely controlled by the relative positions of the cylinder and shaft, any desired marimum being provided through adjustment ol the amount of clearance at the end of a stroke.

l claim:

1. Braking mechanism comprising in cour bination with a pair of rotatable members adapted for variable relative speeds, independent fluid-pressure-generating means operated by each of said members, a common discharge chamber associated with said generating means, and means for controlling the discharge of the fluid from said chamber.

i2. A braking mechanism for revolving shafts operated by differential gearing coniprising force pumps operated independently iwi nto "Whlel ge `from said `"Chamber.

lim!!! s ifbraking;mechanism` ferfrotatable" 1elnbersfaclaptecl forI yarlable relatlye speeds eratelfqby` l l eqnalzingfthe pressure" generated by said,

Claptecl ,ffor Variable relativer speeds, fluid ressnrey1r generatlng [means g yoperated lncle- I ized.'

"l 6 Braking mechanism Colnprsingn cernbinatlon with "a pjar "of, rotatable members adapted a lfer* `variable "relative "speeds,` infr vuclependlent:lncl pressure generating nieans "of said 4members,l anclV y .y

equalzing @he pressnre"`vgeneratecl deemed by each y 'said means."

adapted variable relative `speeds,zijnde `I pendent fl y A y l each" of ling "the io beenfequalzeclg penclently bysafd ndelnbersa fmeansy for equall lzlng the pressure hargellfand means for eontrolllngthellsl" generated independently s y `7L "l Braking mechanism Comprising; in Coni? blnatglnwvlth a palr lnnps eentlnnpns-ly Operated by each.:

of rotatable 'members l said members, nleansl for I llave herennbo" l klancl; this fourth ff D y nid pressure;generating,meansopeu 

